Systems for conveying pressurized fluids, also known as hydraulic systems, have many applications. Generally, hydraulic systems utilize the flow of pressurized fluids for the generation, control, and transmission of forces. For example, hydraulic systems typically are employed to operate the blow-out preventers required to be present on undersea oceanic deep water oil and gas drilling wells. The blow-out preventers forcibly close off a well in the event of a well failure to prevent substantial leakage into the ocean. Should the hydraulic systems fail under such circumstances, substantial environmental damage may occur.
To successfully employ a hydraulic system, a hydraulics circuit must be maintained for the continuous flow of the hydraulic fluid through the system. Typically, hydraulic systems apply force or torque multiplication either by altering the effective areas in two connected cylinders or the effective displacement between a pump and a motor. For the hydraulic fluid to do work, it must be pumped so as to flow from a fluid source to the cylinders or motor, and then return to a fluid reservoir. A disruption or rupture to the fluid pathway in a hydraulic circuit will cause the hydraulic system to fail.
Hydraulic fluid commonly is conveyed through hoses made of rubber-like polymer materials. For example, conventional hoses may be made of a resilient polymeric material formed or extruded over a wire-like or similar metal mesh. The mesh, therefore, is an internal structure in the surrounding resilient material to provide strengthening of the hose material. This provides a balance between a desire for some resiliency to aid in hose manipulation, while having sufficient stiffness to reduce a likelihood of rupture. Such materials thus are rigid enough to maintain the flow of the pressurized fluid without rupturing, but also have a sufficient resiliency for some bending when positioning the hose.
The hose may be joined at one end to a fluid source with a connection nipple. The connection nipple typically is a rigid component. Depending on the application, a connection nipple may be made of a non-corrosive metal, such as stainless steel, or a rigid plastic material. The connection nipple may have a gradually tapered first end that may be inserted into the hose. An opposite second end of the connection nipple may be threaded or otherwise formed with a connector for connection to a hydraulic fluid source. In this manner, the hose may be connected to a hydraulic fluid source. In the area of the joint formed by the hose section and the connection nipple, a clamp typically is provided to secure the hose to the connection nipple, and thereby the fluid source.
Such a clamping system may be employed to repair a ruptured hydraulic circuit so as to reconnect a damaged hose section to the hydraulic fluid source. For example, in the event of a rupture to the hydraulic circuit, the hydraulic circuit may be repaired by severing a damaged hose section from a remaining intact hose section. The remaining intact hose section may then be reconnected to the fluid source using the connection nipple and clamp as described above.
In addition, the longer a conveying hose is, the greater the tendency to have a rupture. The hose, therefore, may be provided in hose sections that are joined using a rigid connection nipple that may be tapered on both sides, and therefore insertable into a hose section at both first and second ends. In the area of a joint between two adjacent hose sections, a clamp also is provided to secure the hose sections. Similarly, in the event of damage to a hose section, the hydraulic circuit may be repaired by severing the damaged hose section from a remaining intact hose section. A new hose section may then be joined to the remaining hose section with a connection nipple and clamp.
It will be appreciated that a joint at the connection between the hose and a hydraulic fluid source, or between two adjacent hose sections, may particularly provide a location for potential failure of the hydraulic circuit. The flow of pressurized fluid tends to exert forces against the hose in both the axial and radial directions. The clamp, therefore, must be able to secure the hose section in the axial direction to prevent the hose from pulling away from the connection nipple. In addition, the clamp must be able to maintain a sufficient compressive radial load against the radial force of the flowing pressurized fluid to seal the hose against the connection nipple, which maintains the hose connection and prevents leakage of the hydraulic fluid.
In harsh environments, such as the oceanic deep water applications referenced above, it becomes even more difficult to properly create and maintain a hydraulic circuit. The joints typically must be made utilizing a robotic remotely operated vehicle (ROV) because the environment is unsuitable for on-site human operation. In such an environment, or any environment that similarly may be associated with extreme temperatures, pressures, or other harsh conditions, clamps have repeatedly failed due to inadequate securing and ejection of the hose from the connection nipple.